Sucrose transport proteins

Abstract

This invention relates to an isolated nucleic acid fragment encoding a sucrose transport protein. The invention also relates to the construction of a chimeric gene encoding all or a portion of the sucrose transport protein, in sense or antisense orientation, wherein expression of the chimeric gene results in production of altered levels of the sucrose transport protein in a transformed host cell.

1 . An isolated nucleic acid fragment encoding all or a substantial portion of a sucrose transport protein comprising a member selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or a substantial portion of the amino acid sequence set forth in a member selected from the group consisting of SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24;   (b) an isolated nucleic acid fragment that is substantially similar to an isolated nucleic acid fragment encoding all or a substantial portion of the amino acid sequence set forth in a member selected from the group consisting of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24; and   (c) an isolated nucleic acid fragment that is complementary to (a) or (b).   
     
     
         2 . The isolated nucleic acid fragment of  claim 1  wherein the nucleotide sequence of the fragment comprises all or a portion of the sequence set forth in a member selected from the group consisting of SEQ ID NO:1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21 and 23. 
     
     
         3 . A chimeric gene comprising the nucleic acid fragment of  claim 1  operably linked to suitable regulatory sequences. 
     
     
         4 . A transformed host cell comprising the chimeric gene of  claim 3 . 
     
     
         5 . A sucrose transport protein polypeptide comprising all or a substantial portion of the amino acid sequence set forth in a member selected from the group consisting of SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24. 
     
     
         6 . A method of altering the level of expression of a sucrose transport protein in a host cell comprising:
 (a) transforming a host cell with the chimeric gene of  claim 3 ; and   (b) growing the transformed host cell produced in step (a) under conditions that are suitable for expression of the chimeric gene   
       wherein expression of the chimeric gene results in production of altered levels of a sucrose transport protein in the transformed host cell. 
     
     
         7 . A method of obtaining a nucleic acid fragment encoding all or a substantial portion of the amino acid sequence encoding a sucrose transport protein comprising:
 (a) probing a cDNA or genomic library with the nucleic acid fragment of  claim 1 ;   (b) identifying a DNA clone that hybridizes with the nucleic acid fragment of  claim 1 ;   (c) isolating the DNA clone identified in step (b); and   (d) sequencing the cDNA or genomic fragment that comprises the clone isolated in step (c)   
       wherein the sequenced nucleic acid fragment encodes all or a substantial portion of the amino acid sequence encoding a sucrose transport protein. 
     
     
         8 . A method of obtaining a nucleic acid fragment encoding a substantial portion of an amino acid sequence encoding a sucrose transport protein comprising:
 (a) synthesizing an oligonucleotide primer corresponding to a portion of the sequence set forth in any of SEQ ID NOs:1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21 and 23; and   (b) amplifying a cDNA insert present in a cloning vector using the oligonucleotide primer of step (a) and a primer representing sequences of the cloning vector   
       wherein the amplified nucleic acid fragment encodes a substantial portion of an amino acid sequence encoding a sucrose transport protein. 
     
     
         9 . The product of the method of  claim 7 . 
     
     
         10 . The product of the method of  claim 8 .